Field of the Invention
The invention relates to a jointed fitting for vehicle seats, in particular motor vehicle seats.
In the known jointed fittings of this kind, the involute toothing of both the first gear wheel with internal toothing and the second gear wheel with external toothing is designed in accordance with the generally accepted principles for involute toothings of gears. For an involute internal toothing, for example, the principle applies that the base circle diameter must be smaller than the top circle diameter or may at the most be equal to the top circle diameter. Because the teeth of the two gear wheels in jointed fittings for vehicle seats are not milled and/or ground, but stamped, the transition from the tooth flank to the head surface cannot be made to include an edge. Instead the teeth must be made with rounded-off heads in order for the stamping tool to have an adequate service life. However, this rounding-off of the heads results in loss of a substantial part of the section of the tooth flanks extending along an involute. This adversely affects the stability of the gear under load and its running performance. To compensate the reduction in the section of the tooth flanks extending along an involute by the rounding-off of the heads, one has heretofore enlarged the teeth and hence also the gear wheels, but this increases the space requirement for the jointed fitting, which, in turn, is inconvenient.